Merge two variables - php

Question

How can I merge two variables?
My code:
$cases = $message->case_number;
$messageText = $message->password;
if (!empty($message->template)) {
$cases = str_replace('_CASE_', $cases, $message->template->text);
$messageText = str_replace('_MESSAGE_', $messageText, $message->template->text);
}
How can I merge $cases and $messageText?
Edit for clarity, from comments below
I want to replace $messageText with MESSAGE and $cases with CASE in just 1 variable something like
$test= str_replace('CASE', $cases, 'MESSAGE',$messageText, $message->template->text);

Answer 1

You can pass both replacement items in to array_replace() at the same time using an array...
if (!empty($message->template)) {
$output = str_replace(['_CASE_', '_MESSAGE_'],
[$cases, $messageText],
$message->template->text);
}

Answer 2

Use the dot to concatenate strings, like this:
$firstname = 'Dave';
$middlename = 'Brexit';
$lastname = 'Davis';
$fullname = $firstname . ' ' . $middlename . ' ' . $lastname; // 'Dave Brexit Davis'

Answer 3

You can always merge two or more variables together by just putting dot between them.
$cases = $message->case_number;
$messageText = $message->password;
if (!empty($message->template)) {
$cases = str_replace('_CASE_', $cases, $message->template->text);
$messageText = str_replace('_MESSAGE_', $messageText, $message->template->text);
$merged = $cases.$messageText;
}